This research will investigate PT. Astra Daihatsu Motor to producing Main Body. The production process has quality standard which set company, this research will analyze quality control Main Body production which is on production we still found defect so that do not reach target quality. The research method use to processing the production defect data from Main Body is Statistical Process Control (SPC) then the result will be analyzed by Cause and Effect Analysis method. The result of this research can be concluded that quality control in PT. Astra Daihatsu Motor requires improvement. Because of the graphic which is SPC method shown fluctuating and irregular points that indicating the production process is deviate.